Mechanical Properties and Scratch Test Studies of New Ultra-hard AlMgB14 Modified by MWCNTs

Abstract

The composites AlMgB14 with MWCNTs were prepared by mechanical alloying (MA) and field activated and pressure assisted synthesis (FAPAS) process. Determination of microhardness and fracture toughness indicated that MWCNTs was an effective addition for increasing both quantities. The optimum percent MWCNTs addition corresponding to the highest hardness and fracture toughness was 0.5 wt%. The abrasion resistance of AlMgB14 composites with varying amounts of MWCNTs has been studied using single-point diamond scratch tests with loads ranging from 10 to 100 N in 10 N increments. The scratch width increased almost linearly with the applied load and decreased with increasing MWCNTs proportion up to 0.5 wt%. Furthermore, macroscopic abrasion resistance increased with both mean hardness and fracture toughness. Cracks were not observed on the surface of AlMgB14−0.5 wt% MWCNTs when scratched under 100 N load, there was no cracking in the absence of MWCNTs too.